Since Pokémon Go's launch last summer, there have been plenty of anecdotal news reports and social media mentions of players being hurt or even killed while playing the game. A new study from Purdue University, though, uses detailed local traffic accident reports to suggest that Pokémon Go caused a marked increase in vehicular damage, injuries, and even deaths due to people playing the game while driving.

In the provocatively titled "Death by Pokémon Go" (which has been shared online but has yet to be peer-reviewed), Purdue professors Mara Faccio and John J. McConnell studied nearly 12,000 accident reports in Tippecanoe County, Indiana, in the months before and after Pokémon Go's July 6, 2016 launch. The authors then cross-referenced those reports with the locations of Pokéstops in the county (where players visit frequently to obtain necessary in-game items) to determine whether the introduction of a Pokéstop correlated with an increase in accident frequency, relative to intersections that didn't have them.

Getting at causation

While the incidence of traffic accidents increased across the county after Pokémon Go's introduction, that increase was a statistically significant 26.5 percent greater at intersections within 100 meters of a Pokéstop, compared to those farther away. All told, across the county, the authors estimate 134 extra accidents occurred near Pokéstops in the 148-day period immediately after the game came out, compared to the baseline where those Pokéstops didn't exist. That adds up to nearly $500,000 in vehicle damage, 31 additional injuries, and two additional deaths across the county, based on extrapolation from the accident reports.

The study uses a regression model to account for potential confounding variables like school breaks and inclement weather, which could cause variation separate from Pokémon Go. The model also compares Pokéstops to Pokégyms (where it was nearly impossible to play while driving) to account for the possibility that generally increased traffic to Pokémon Go locations was leading to more accidents, even among drivers who stopped and parked before playing. In all cases, though, being able to compare to intersections without a Pokéstop and to the same dates the year before, helped provide natural control variables for the study.

Further Reading

Other data points also suggest Pokémon Go as the main culprit in the shift. For instance, the relative increase in accidents at these locations tracked closely with the reported Daily Active Users for the game worldwide, which peaked in July and fell steadily through November (the last month in the study). The effect is also measurably reduced as you increase the observed distance from a Pokéstop between 50 and 500 meters. And the traffic reports themselves show a disproportionate increase in "distracted driver" as the listed cause for intersections near Pokéstops after the game's release (though a limited sample size and problems with self-reported causes complicate this last data point).

Is this a big problem?

While the authors warn that extrapolating one county's results to the entire country is "speculative," the totals here suggest more than 145,000 additional crashes, 29,000 additional injuries, and 250 additional deaths could have been caused by playing Pokémon Go while driving in the five-month period following the game's release. And that doesn't even account for distracted players getting into accidents farther away from Pokéstops while searching for wild Pokémon or simply looking for unknown locations.

Developer Niantic hasn't ignored Pokémon Go's potential for causing distracted driving. Starting last August, an update to the game warned players in fast-moving vehicles that "You’re going too fast! Pokémon Go should not be played while driving," and asked them to confirm they were a passenger before continuing. Then, starting last November, Niantic began making the game virtually unplayable in a fast-moving vehicle, even for passengers.

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Kyle Orland
Kyle is the Senior Gaming Editor at Ars Technica, specializing in video game hardware and software. He has journalism and computer science degrees from University of Maryland. He is based in the Washington, DC area. Emailkyle.orland@arstechnica.com//Twitter@KyleOrl

63 Reader Comments

Unfortunately, the ability to claim you're not driving and then use apps like this anyway is leading to things like the article's mentioned crackdown on use even by passengers. But given that those features are probably being abused by people who are actually driving, the override is probably sorely needed.

Even the "do not disturb while driving" feature of iOS 11 (which works pretty reliably, in my experience; it knows when it's connected to a car Bluetooth and when it is moving in a way that probably indicates it's in a vehicle) has an "I'm not driving" toggle that is probably routinely lied to by text-addicted drivers.

The problem, of course, is how do you reliably tell who's the driver and who's the passenger? The answer is probably going to require newer vehicles that can tell where in the car a signal is coming from, and I don't see that happening any time soon because there's no market pressure or regulation requiring such equipment to be fitted. And even then, how do you enforce it on the phone itself to obey the car's signals of "this is a driver, do not allow use"?

This seems like an overly-branded way of saying that "using your phone while driving leads to increased accidents", which has been a known fact since the mass adoption of cell phones nearly 20 years ago.

Granted, the numbers specifically tied to Pokemon Go are pretty high, but how much are they stacked against texting while driving?

This seems like an overly-branded way of saying that "using your phone while driving leads to increased accidents", which has been a known fact since the mass adoption of cell phones nearly 20 years ago.

Granted, the numbers specifically tied to Pokemon Go are pretty high, but how much are they stacked against texting while driving?

I think they chose this app because it's well known, because the time of its introduction to the public is a matter of historical record, and because it is easy to look on a map and see where the "hot spots" are that lead to people interacting with the game at those spots.

Texting, by comparison, can happen at any time and in any location. So the correlation is harder to confirm.

I wonder if there was a decrease of accidents at the time the Pokemon Go Plus was released (and when it was restocked a few months later).

Go Plus is a lot safer for people that play and drive, not needing to look at their phone while gathering PokeStops and taking attempts at Pokemon.

Edit:Go Plus was released September 16th, 2016. There was a big drop off in September 2016 while they went back up in October.Of course that could account for students being back in school. And can not recall if they had a Halloween event last year.

This seems like an overly-branded way of saying that "using your phone while driving leads to increased accidents", which has been a known fact since the mass adoption of cell phones nearly 20 years ago.

Granted, the numbers specifically tied to Pokemon Go are pretty high, but how much are they stacked against texting while driving?

Like all applied econ papers the question is what do you have data on that you can actually measure? Often the data that allows a clean(er) estimation is going to limit your generalization, but paired with other such studies you can start to paint a bigger picture.

This seems like an overly-branded way of saying that "using your phone while driving leads to increased accidents", which has been a known fact since the mass adoption of cell phones nearly 20 years ago.

Granted, the numbers specifically tied to Pokemon Go are pretty high, but how much are they stacked against texting while driving?

I think they chose this app because it's well known, because the time of its introduction to the public is a matter of historical record, and because it is easy to look on a map and see where the "hot spots" are that lead to people interacting with the game at those spots.

Texting, by comparison, can happen at any time and in any location. So the correlation is harder to confirm.

Well we already have studies on texting while driving, we know that it causes an increase in accidents.

This is mildly interesting because it shows that Pokemon Go specifically was popular enough and dangerous enough to actually rise out of the existing noise of accidents (that would include texting). Not sure how much I trust it though, I take studies like this with a grain of salt nowadays.

While the authors warn that extrapolating one county's results to the entire country is "speculative," the totals here suggest over 145,000 additional crashes, over 29,000 additional injuries, and over 250 additional deaths could have been caused by playing Pokémon Go while driving in the five-month period following the game's release. And that doesn't even account for distracted players getting in accidents farther away from Pokéstops, while searching for wild Pokémon or simply looking for unknown locations.

While the authors warn that extrapolating one county's results to the entire country is "speculative," the totals here suggest over 145,000 additional crashes, over 29,000 additional injuries, and over 250 additional deaths could have been caused by playing Pokémon Go while driving in the five-month period following the game's release. And that doesn't even account for distracted players getting in accidents farther away from Pokéstops, while searching for wild Pokémon or simply looking for unknown locations.

I personally hate when professionals do this. It's fear mongering BS.

It's called extrapolation, and the provisions that limit the extrapolation's relevance were part of the comment, thus eliminating the hype factor that would accompany "fear mongering".

If this was fear mongering, the limitations would be gone and the authors would have simply said, "Based on this study, hundreds of thousands of additional crashes, tens of thousands of additional injuries and hundreds of additional deaths have been caused in only a few short months after the Pokemon Go was released! Hide your children!"

I find this all very specious. Pokemon Go didn't cause these accidents, people making bad choices caused the accidents. What's more, there is nothing indicating that it was confirmed that these accidents were directly caused by Pokemon Go, only speculation and correlation.

I really despise these "studies" that claim to show X caused Y because, correlation. I could claim that old age causes death with the same level of accuracy, but I know that it's false. Disease causes death. Old age just makes it harder to resist disease. These studies are the bane of proper science.

While the authors warn that extrapolating one county's results to the entire country is "speculative," the totals here suggest over 145,000 additional crashes, over 29,000 additional injuries, and over 250 additional deaths could have been caused by playing Pokémon Go while driving in the five-month period following the game's release. And that doesn't even account for distracted players getting in accidents farther away from Pokéstops, while searching for wild Pokémon or simply looking for unknown locations.

I personally hate when professionals do this. It's fear mongering BS.

That's not fear mongering. Fear mongering is done by "journalists" who then write a news article claiming those larger numbers as facts presented by the authors.

While the authors warn that extrapolating one county's results to the entire country is "speculative," the totals here suggest over 145,000 additional crashes, over 29,000 additional injuries, and over 250 additional deaths could have been caused by playing Pokémon Go while driving in the five-month period following the game's release. And that doesn't even account for distracted players getting in accidents farther away from Pokéstops, while searching for wild Pokémon or simply looking for unknown locations.

I personally hate when professionals do this. It's fear mongering BS.

It's not necessarily confirming 'common sense'. It's one thing to know that distracted drivers are more likely to have accidents, and that's well established - so one could extrapolate that playing Pokemon Go was just another distraction likely to cause accidents.

It's an entirely different thing to discover that, not only were people distracted while driving, they were potentially specifically driving because of the game, to get to new spots or hard to reach spots. I don't think any previous study has shown anything on a phone has specifically caused people to both drive and subsequently get into an accident.

Unless the county that they did the study in is in fact representative of the country, as in an "average" county, it's serves no other purpose.

No different that if I took the murder rate of Cook county Illinois and "extrapolated" that out to the whole country. It would be complete off base and useless.

This is no different. The extrapolation has no good reason to be done other than to try to inflate numbers high enough to catch people's attention. 148 extra accidents doesnt carry near the impact that 150,000 extra crashes does.

Exercise personal responsibility and recognize that using your phone while driving is as thoughtless and dangerous as drunk driving. Try to not to fall in to the trap of convincing yourself it's not that serious or you can handle it.

Then, starting last November, Niantic began making the game virtually unplayable in a fast-moving vehicle, even for passengers.

This ruined the fun of driving around with the family in the car getting Pokestops and catching Pokemon. It wasn't too difficult for a passenger to play on both their phone and the driver's phone so the driver could concentrate on driving.

I would still expect there to be increased traffic and being directed to slow down or make a turn on short notice that could contribute to accidents even if they aren't playing the game themselves. If you attract more people to an area, especially an area they don't go to often, you will get more accidents.

I'm sure that Pokestops on walking trails in parks are much safer, and actually encourage exercise, but there are also limitations on how many restrictions you should place on everyone in the interest of trying to stop irresponsible people from being irresponsible.

Those poke-stops existed as Ingress portals for (in most cases) around 2-3 years prior to Poke-go launch, and 'cargress' is definitely a thing. I wonder if they could use the same methods to show a correlation with the portal go-live dates (assuming they could get those from Niantic, or possibly a player organized data-scraping group >.<)

I find this all very specious. Pokemon Go didn't cause these accidents, people making bad choices caused the accidents. What's more, there is nothing indicating that it was confirmed that these accidents were directly caused by Pokemon Go, only speculation and correlation.

I really despise these "studies" that claim to show X caused Y because, correlation. I could claim that old age causes death with the same level of accuracy, but I know that it's false. Disease causes death. Old age just makes it harder to resist disease. These studies are the bane of proper science.

Agreed, Pokemon Go isn't the cause of the collisions. What this study is arguing is that it is a catalyst. And while correlation does not always imply causation, it is a greater fallacy to argue - as you are - that correlation never implies causation.

This is perfect. I took a lot of grief from other parents for pulling my daughter out of a carpool after she reported that one of the parents routinely chased Pokemon and watched YouTube while driving*. I'll share this with all of them, not that they'll care or feel it's an issue.

Unless the county that they did the study in is in fact representative of the country, as in an "average" county, it's serves no other purpose.

No different that if I took the murder rate of Cook county Illinois and "extrapolated" that out to the whole country. It would be complete off base and useless.

This is no different. The extrapolation has no good reason to be done other than to try to inflate numbers high enough to catch people's attention. 148 extra accidents doesnt carry near the impact that 150,000 extra crashes does.

You're changing the goalposts.

Fear mongering is hyping something beyond reason by implying things that aren't necessarily true. This wasn't hyped in any way. The fact is, their figures COULD be correct, and are exact, and calculated based on extrapolation.

148 extra crashes in Cook County Il is statistically significant (assuming traffic-accident influencing events are accounted for), even if they only accounted for a small fraction of total accidents. The same can be said for deaths and injuries.

Extrapolation offers a means of seeing how significant of a problem it COULD be, not how much it actually is. And they stipulated that in their write-up.

I mean, if you're reading "fear mongering" in that, you need to redefine your understanding of what it is. Otherwise, you seem to be badly rationalizing a critique of studies that indicate there's a physical risk to players who aren't bright enough to avoid driving while simultaneously hunting down a virtual monster.

One might quibble about the level of risk, but you can't deny there's risk involved if one isn't aware of it. And what's the point of the extrapolation?

How about making people more aware that driving and hunting is a retarded thing to do?

I find this all very specious. Pokemon Go didn't cause these accidents, people making bad choices caused the accidents. What's more, there is nothing indicating that it was confirmed that these accidents were directly caused by Pokemon Go, only speculation and correlation.

I really despise these "studies" that claim to show X caused Y because, correlation. I could claim that old age causes death with the same level of accuracy, but I know that it's false. Disease causes death. Old age just makes it harder to resist disease. These studies are the bane of proper science.

Falling off a cliff is a chose and two Pokemon Go players did exactly that last year. Those players survived.

People continue to get hurt and die due to Pokemon Go. It now even has its own tracker.

Unless the county that they did the study in is in fact representative of the country, as in an "average" county, it's serves no other purpose.

No different that if I took the murder rate of Cook county Illinois and "extrapolated" that out to the whole country. It would be complete off base and useless.

This is no different. The extrapolation has no good reason to be done other than to try to inflate numbers high enough to catch people's attention. 148 extra accidents doesnt carry near the impact that 150,000 extra crashes does.

You're changing the goalposts.

Fear mongering is hyping something beyond reason by implying things that aren't necessarily true. This wasn't hyped in any way. The fact is, their figures COULD be correct, and are exact, and calculated based on extrapolation.

148 extra crashes in Cook County Il is statistically significant (assuming traffic-accident influencing events are accounted for), even if they only accounted for a small fraction of total accidents. The same can be said for deaths and injuries.

Extrapolation offers a means of seeing how significant of a problem it COULD be, not how much it actually is. And they stipulated that in their write-up.

I mean, if you're reading "fear mongering" in that, you need to redefine your understanding of what it is. Otherwise, you seem to be badly rationalizing a critique of studies that indicate there's a physical risk to players who aren't bright enough to avoid driving while simultaneously hunting down a virtual monster.

One might quibble about the level of risk, but you can't deny there's risk involved if one isn't aware of it. And what's the point of the extrapolation?

How about making people more aware that driving and hunting is a retarded thing to do?

If that's "fear mongering" bring more of it on!

I'll concede that fear mongering isnt the best choice of words. But I wont concede that the extrapolation isnt exactly as I stated it was. Non-necessary to inflate numbers to cause the common citizen to take notice. (my understanding of what fear mongering is, using statistics to increase the perceived threat) Which you seem to indicate is what they did with your last question. Simply saying hey, we pretty much know for a fact 148 extra accidents were because of pokemon go isnt going to be enough. Sooo..they extrapolate that out to a big enough number that they can catch the attention of the common idiot.

Perhaps you can tell me a better word for such as this, Mr Wordsmith.(not being snarky here, you're an author if I recall correctly.)

Unfortunately, the ability to claim you're not driving and then use apps like this anyway is leading to things like the article's mentioned crackdown on use even by passengers. But given that those features are probably being abused by people who are actually driving, the override is probably sorely needed.

Even the "do not disturb while driving" feature of iOS 11 (which works pretty reliably, in my experience; it knows when it's connected to a car Bluetooth and when it is moving in a way that probably indicates it's in a vehicle) has an "I'm not driving" toggle that is probably routinely lied to by text-addicted drivers.

The problem, of course, is how do you reliably tell who's the driver and who's the passenger? The answer is probably going to require newer vehicles that can tell where in the car a signal is coming from, and I don't see that happening any time soon because there's no market pressure or regulation requiring such equipment to be fitted. And even then, how do you enforce it on the phone itself to obey the car's signals of "this is a driver, do not allow use"?

Or you know, police could move their monetizing of roadways off of speeding and registration tickets and onto distracted drivers. Distracted drivers cause more accidents than alcohol. Speeding without distraction is a rounding error to distracted drivers at or below the speed limit.

Cars don't need more built in nannies. People need to change behavior. I make the same argument about automatic headlights because it is consistent that once people get used to them, they are constantly driving in conditions (e.g. rain with bright grey skies) where their lights should be on and aren't. Again, this is a matter where law enforcement could get involved, but choose not to make an effort (just stop the retards and give them a warning about road conditions and visibility).

I really despise these "studies" that claim to show X caused Y because, correlation. I could claim that old age causes death with the same level of accuracy, but I know that it's false. Disease causes death. Old age just makes it harder to resist disease. These studies are the bane of proper science.

They are using a standard difference in difference measure: more or less compare before and after a Pokestop is introduced to before and after another location that is not a Pokestop. They have enough data before the "treatment" to test whether the treated locations had different pre existing trends. Looking at their figure 1, I am a little concerned with seasonality, but in their regressions they state they control for school breaks. The evidence here is not bad, and is a lot better than other articles written about on Ars like the following that don't even attempt to do this:

The nice thing about (time X location) data is that they can include both time and location fixed effects in addition to other controls. Unobservables that are time invariable or location invariant are controlled for. They are picking up an increase in accidents when there is that Pokestop, so if it is something else driving this not connected to the Pokestops, it is quite the coincidence. For example, a place that is busy when school is out is also more likely to be a Pokestop when school is out could be a problem, but they have a method to at least partially control for this. What is nice is that the impact seems to vary with the number of overall players, which is highly suggestive.

The do consider alternative explanations to inattentiveness e.g. more traffic caused by the Pokestop itself and more pedestrians at the location. The best evidence they have for inattentiveness are the police reports citing the driver inattentiveness, but to some extent all these factors will be at play.

For example, they have to specify how far a distance from a Pokestop is relevant for their model. What is nice about this paper though is that they do vary that distant and the effect dissipates as distance increases.

Of course all the above is conditional on no coding errors etc., which is not something peer review picks up on most of the time.

Side note since not passing peer review was mentioned in the original article, whether this paper is "significant" because it passed peer review is not all that important in my opinion since econ papers take a while to get through peer review. This is why working paper outlets are useful.

I really despise these "studies" that claim to show X caused Y because, correlation. I could claim that old age causes death with the same level of accuracy, but I know that it's false. Disease causes death. Old age just makes it harder to resist disease. These studies are the bane of proper science.

They are using a standard difference in difference measure: more or less compare before and after a Pokestop is introduced to before and after another location that is not a Pokestop. They have enough data before the "treatment" to test whether the treated locations had different pre existing trends. Looking at their figure 1, I am a little concerned with seasonality, but in their regressions they state they control for school breaks. The evidence here is not bad, and is a lot better than other articles written about on Ars like the following that don't even attempt to do this:

The nice thing about (time X location) data is that they can include both time and location fixed effects in addition to other controls. Unobservables that are time invariable or location invariant are controlled for. They are picking up an increase in accidents when there is that Pokestop, so if it is something else driving this not connected to the Pokestops, it is quite the coincidence. For example, a place that is busy when school is out is also more likely to be a Pokestop when school is out could be a problem, but they have a method to at least partially control for this. What is nice is that the impact seems to vary with the number of overall players, which is highly suggestive.

The do consider alternative explanations to inattentiveness e.g. more traffic caused by the Pokestop itself and more pedestrians at the location. The best evidence they have for inattentiveness are the police reports citing the driver inattentiveness, but to some extent all these factors will be at play.

For example, they have to specify how far a distance from a Pokestop is relevant for their model. What is nice about this paper though is that they do vary that distant and the effect dissipates as distance increases.

Of course all the above is conditional on no coding errors etc., which is not something peer review picks up on most of the time.

Side note since not passing peer review was mentioned in the original article, whether this paper is "significant" because it passed peer review is not all that important in my opinion since econ papers take a while to get through peer review. This is why working paper outlets are useful.